Electric liquid heater



Aug. 19, 1952 L, BOWEN 2,607,878

ELECTRIC LIQUID HEATER Filed Aug. 8, 1950 2 SHEETS--SHEET l ESL /E G. BOWEN 7,19 I 2j i @9'4" I Ar//y Aug. 19, 1952 l.. G. BOWEN ELECTRIC LIQUID HEATER 2 SHEETS--SHEET 2 Filed Aug. 8, 1950 INVENTOR.

ESL/E G. BOWEN w a n .m 4 E/a Patented Aug. 19, 1952 UNITEDSTATES PATENT orifice ELECTRIC LIQUID HEATER Leslie G. Bowen, Evanston, Ill. Appli'catinn August 8, 195o, serial No. 178,257

' 15 Claims.

l u 1 i My invention relates to liquid heaters, and more particularly to an electric liquid heater.

1t is the principal purpose of my invention to provide a heater for heating liquid to a high temperature rapidly, that is adapted to be located in a restricted space, particularly a space that is-restricted in vertical dimension. In connection with the use of glasses, dishes fand other utensils, in public places, it is a health requirement in many communities that theseglasvses, dishes and utensils be sterilized by means of water at a high temperature slightly below thel boiling point of water. The ordinary tank water heater does not heat water to a high enough temperature at the point of use without the possibility of boiling the water in the heater, to accomplish this purpose. Accordingly one of the important uses of my heater is to raise the-temperature of water obtained from the ordinary hot water system supplied by means of a tank heater, rapidly to a temperature such that it is high enough for the sterilization of glasses and similar vessels. In order to accomplish this, ordinarily relatively small quantities of water at a temperature slightly below the boiling point, are required at frequent intervals, and my improved liquid heater is constructed to accomplish such heating. i d

While my improved liquid heater is particularly adaptedrfor use for heating water for the above referred to purpose, in restricted spaces in which the heater has to be placed, if it is to be closely adjacent the point of useof the Water, it is also adapted for use in heating other liquids for other purposes to high temperatures rapidly.

In order to accomplish the above referred to purpose, my improved liquid heater comprises a housing that is divided into a pair of compartments by means of a partition and which has heat-ing means in each of the compartments, the inletvand outlet end connections and connection between the compartments Vbeing so arranged that the liquidy iiowing into one compartment has to iiow around the heating means in said compartment to pass into the other compartment and has to flow around the heating means in said other compartment before it reaches the outlet in said other compartment to which suitable conduit means may be `connected vfor conveying the Water or similar liquid to the point of use. The compartments are preferably of such size that the amount of liquid used each time that liquid is withdrawn from the second mentioned compartment is all withdrawn from said second compartment, and liquid that has previously been heated in the rst compartment passes into the second compartment to take the place of the liquid that was used, the Water or other liquid entering the rst mentioned compartment toV be heated therein preliminary to passing into the second compartment. Thus the rst compartment serves as a pre-heating compartment and the second compartment serves as means for heating the liquid to the temperature at which it is to be used.

It isa particularly important purpose of my invention to provide a heating device in each of the compartments that also acts as baiing means in the compartment, so that if the apparatus is used inthe preferred manner-the heating means will provide a baille that inclines upwardly from the inlet side of each compartment toward-:the outlet side of each compartment. This will cause the liquid that is at the lowest temperature in the particular compartment to travel upwardly along the inclined wall, either on the lower lor upper face thereof and thus circulate in said compartment.

Furthermore my invention Acomprises a heating device in each compartment. that has, not only a Wall that serves as a baille, but iins thereon that, in cooperation with the walls of the compartment, serve as means to provide liquid heating chambers or passages in each compartment, each of which has either an inclined bottom wall or an inclined top wall, and each heating passage or chamber is provided with walls that are highly heated on three sides thereof, thus rapidly heatingthe liquid in each passage or chamber. The iins on the baille member and the baiiie member extend into adjacency with the walls of the compartments, so that these heating chambers or passages are formed. There is an opening provided establishing restricted communication between the one end of each chamber or passage and the chamber or passage vertically adjacent thereto, to thus control the circulation of liquid in each of the passages or chambers and prevent the too rapid passage thereof from the inlet into the lower chambers and to the outlet from the upper chambers.

It is another important purpose of my invention to provide heating means in each of the compartments, that isso constructed and arranged that the same can be readily removed from the compartments and cleaned. In order to facilitate cleaning of the heating means in each compartment, the baille members and the iins are provided with iiat faces andthe ns extend in relatively widely spaced relation perpendicularly that include aluminum, and are of high heat K accus-ive conductivity, in which is cast a heating element that is provided with an outer metallic sheath, in which a resistance element is provided, which resistance element is insulatingly mounted within the sheath so that the heating element-with theA sheath thereon can be cast directly inthe aluminum or similar metallic body portion of the" heating device and yet be electrically insulated therefrom. As a result of this mounting of the heating element or elements' in the metallic body portion of the heating device, the heating element is in direct heat conducting relation to theV metal of the heating device Vand the body portion of the heating device or baiile 'and the fins thereon are both heated to substantially the same temperature throughout. K

It is another important purpose oi m invention to provide means for controlling the operation ofv the heating elements in the heating means,l comprising a thermostatic element or elements, so mounted as Yto be in closely spaced relation -to -a-heatin'g device in one of the compartments. This is done in order to `assure the operationnofy the thermostatic controlling means even should there be no water in the compart- I ments, `as the proximity of the thermostatic means to the heating device will cause the thermostaticelement to 'open the circuit, should the heating device become overheated in case no water is in the compartment.` Ordinarily the water in the second or outlet compartment will surround the thermostatic controlling device in such a manner'as to operate the same todiscon- Vtinue operation of the heating means in the second or outlet compartment of the liquid heater when the temperatures therein reaches from 190 to 195.

It has been vfound desirable in certain instances to provide means for controlling the yheating of the heating means in the compartments in such a manner that heating is continued beyond the temperature at which the above referred to thermostatic means will break the circuit to the heating element abovereferred to. In order to accomplish this, two heating elements are provided in each of the heating means each compartment and one heating element of each pair is controlled by the thermostat above referred to,

' while the second heating element in each compartment is controlled by another thermostat, that is provided in the first or inlet compartment, and which is actuated to break the circuit to said second heating element upon a lower temperature being reached in said first or inlet compartment, preferably, about 165. i

By providing such a control the heating apparatus lwill operate in a similar manner to a storage heater, in that a reserve supply of heated liquid will be available after the thermostatic element in the outlet compartment has operated to shut off one heating element of each pair, as the controlling means for the second heating element will permit heating Vto continue beyond that 4 obtained from the first heating element. Said second controlling means is so set that it will discontinue all heating before the temperature in the outlet compartment reaches the Iboiling point of the liquid, such as the boiling point of Water, for example. However, should water be withdrawn from the outlet compartment, which will not immediately aiect the thermostat in the outlet oompartment,it will-aiect the thermostat in the inlet compartment, as coolerwater is entering the inlet compartment. This will cause the heating elements controlled by this thermostat to beenergized to begin heating the water before the thermostatic control in the outlet compartment Will close the circuit to the heating elements it controls, so that the time interval for bringing tewater in the outlet compartment again up .to themaximum temperature suitable for use for 'sterilizing will be shortened.

Other objects and advantages of my invention will appear-fas the description of the drawings proceeds; desire to have it understood, however, that I do not intend to limit myself to the particular details shown or described, except as defined in the claims;

In the drawings:

Fig; 1 is a horizontal section of the improved single element heater, immediately 'below 'the top wall thereof.

Fig. is a verticalsection 'taken on the line of Fig. l.

Fig. 3 is a lwiring Vdiagram of the single ele'- Y ment heater circuit.

Figpfl is a detail'section through a terminal of oneof the heating elements. p

Fig. 5 is a horizontal section, similar to "Fig 1, of the double element typegheater.

Fig. 6 is a vertical section taken on the line --S of Fig. 5, and

Fig.' 7 Vis a wiring diagram of the double elementheater circuit. l y

YReferring in detail 'to the drawings, my improved Iiquid heater 'shown lin Figs. l and L2 comprises a housing l0 fdivided Vinto a pair of compartme'rits Il and I2 by a partition I3.V A baffle i Zi in compartment H' anda baffle AI5 in compartment I2 each contains a single heating element i6. The housing I0 is of a double wall construction with heat insulating material l' between said walls. The outerwall |'8 is fastened to the inner wall E9 by suitable` fastening elements 2t. Agasket 2l is provided between-the end Wall 22 and the inner wall'lB and partition 13. A- c'o'ver 23 is 'secured to the'end `wal-1 by fastening 'ele'- ments 2a. Fastening elements 324 also secure ythe vend wall 22 to the inner compartment walllS.

y The baiii'e I4 is secured rigigy to the end wall 22 bynuts 25'on the threadedportions 2S of the heating element i6, whichis cast within said baille. The baiiie i4 is providedfwith nns 32 havin-g vtheir marginal edges Alying adjacent the 'inner walls of the compartments and with Said walls form a pluralitypofliquid heating chambers. ./ls shown in Fig. 2, the baffle Il is inclined rom the-inlet sideof compartment I'l upwardly to the 'Outlet Side Cf CIpaTtmeIi-t Il, andr Snlilarl'y the baille i5 is inclined upwardly from the inlet side of compartimenti? to the outlet'side thereof. The bailies I4 and f5 have 'parallel faces 33 and Sil, from which the parallel iins 32 extend perpendicularly. Circulation, as shown by the arrows in Fig. 2*,'is caused Within each chamber because of the inclination ofthe bailie I Il, the water or other liquidtendi'ng to travel up said inclined faces as it is heated.

Liquid ilow Within the heater 'progresses from the inlet 35 of'compartment II .and successively through the chambers inlsaidcompartment lying side bysideto the outlet 36 of compartment II. The outlet 36 of compartment II also serves as the inlet for compartment I2 and the iiow progresses in the same manner successively through the chambers lyingside by side in said compartment I2 to the outlet 31, across the fins 32 on baffle I5. 4In both compartments the inlet is located in the diagonallyopposite corner from 'the outlet to provide the same distance fromsaid inlet to said outlet both above and below the baiile. The flow from each chamber to the horizontally adjacent chambers in each compartment takes place in `.therestricted space between the edge of the fin 32 and the adjacent wall of the compartment. A thermostatic switch 38 is provided near the outlet 31- in the nal chamber of compartment I;2, said switch 38 havingy a tubular housing 5I for the thermostatic element thereof extending through openings 52 in a plurality of the fins 32.

The heating elementsy IB in the baiiles I4 and I5 are of a well known type, consisting of a hollow tube 21 containing aresistanceiwire 28`and ceramic insulating material 29 between said wire andsaid tube. Electrical insulating means 30 is provided between the terminal 3I and the tube 21. The hexagonal nut 39 is welded to the tube 21 to prevent rotation of the tube after it is cast integral with the baflles I4 and I5. The circuit for the single heating element baffles I4 and I5 is shown in Fig. 3, the heating elements I6 in said baffles being connected in series with each other and with the thermostatic switch 38, between the conductors 42 and43 leading from a suitable source of electricalenergy. g It will be noted that the baffles I4 and I5 have their lower marginal edges 44 located closely adjacent the bottom walls and the side walls at the inlet sides of theA compartments II and I2, respectively, andtheir upper marginal edges 45 located closely adjacent the top walls and the side walls at the outlet sides of the compartments II and I2, respectively. The n 32 at the inclined marginal edge of each of the baiiies I4 and I5 adjacent the end wall 22 is spaced therefrom by the mounting lug 46 provided on each bale, which is clamped against the end wall 2 2 by the nuts 25 engaging the threaded portions 28, vso that said baiiles are removable as a unit with said end wall 22. The mounting lugs46 space the marginal fins 32 from the end wall 22t0 reduce conduction of heat from said iins to said end wall'and to provide inlet and outlet chambers into which the inlet connection 35 and from which the outlet connection 31 leads, respectively.

The fins 32 have their marginal edges lying closely adjacent the walls of each compartment, said ns gradually increasing in height from the corners 41 thereof lying endwise beyond the marginal edges 44 and 45 of the baffles to the corners 48 thereof. -The bales, ns and adjacent walls of the compartments thus provide a series of horizontally adjacent elongated chambersabove and below said bafes, the vertically adjacent chambers betweenvertically aligned fins being in communication through the restricted-passages 49 and 50 between the marginal edges 44 and 45 and the compartment walls.

In the form of my invention shown in Figs. 5 and6 my liquid heater comprises a housing, I8 divided into a pair of compartments I I and I2 by a partition, as 'in the previously described form.

CII

thermostatic elements The baile I4'lin compartment II and the baie I5' in compartment I2 each contain two heating' elements II and 40. The liquid ow through each compartment around the fins from chamber rto chamber is the same as previously described. An additional thermostatic switch 4I is provided in chamber II to control the heating elements 48, as will be described below. The thermostatic switch 438 in chamber I2 controls the heating elements I6 in the same manner as in switch 38.

Referring tothe circuit diagram in Fig. 7, the heating elements I6 are in series with each other and with the thermostatic switch 38' andthe resistance elements 40 are in series with each other and with the thermostatic switch 4I, the

switches 38 and 4I being thesame in construction as the switch 38. The conductor 53 and the conductor 54 lead from a suitable source of electrical energy. From the conductor 53 the branch lines 55 and 5B lead to oneend of one of the resistances IE and 4U, respectively, while the branch lines 51 and 58 lead from the thermostatic elements 4I and 38', respectively; to the conductor 54. Thus the heating elements or resistances I6 Yare connected in series and the resistance elements 46 are connected in series, but the resistance elements I6 and 40 are in parallel with each other, as are the thermostatic elements 38 and 4l The baffles I4` and I5 and the baffles I4 and I5 are alike in construction except for the inclusion of a pair of heating elements in the baiiles I4 and I5 and the provision of considerably larger clamping lugs 46 onthe bales I4 and I5', prov viding for the mounting of the additional terminals 3| which are identical with the terminals 3I, but areconnected with the heating velement 46. As all the other parts of the apparatus are the same in the form shown in Figs. 5 and 6 yas that shown Yin Figs. l and 2, the same reference numerals are applied to corresponding parts thereof.

noted that the housings 5I for the of the thermostatic switches 38, 3B and 4I extend through the openings 52 in a plurality of the ns 32 in the lower portions of the compartments I2 and I I and that these tubular housings 5I are closely adjacent, but spaced slightly from the walls of the openings 52 in said fins. Thus the thermostatic elements in the tubes 5I will be caused to operate to open the circuit if the temperature of the adjacent ns exceeds the temperature, at which the adjustable thermostatic elements 38, 38' or 4I are set, to any great extent, even ii' no water is in the compartments II and I2, as the air in the narrow space surrounding the tubular member 5I will transfer the heat from the iin 32 having such an opening 52 to the tubular member 5I and thus kto the therinostatic element, but when water is in the compartment I2, or in the compartments I I and E2 in the form of the invention shown in Figs. 5 and 6, the thermostatic elements will be responsive to the temperature of the water and It will be not to the temperature of the n 32 adjacent said tubular member 5I. I'

In the operation of my liquid heater as shown in Figs. 1 and 2, preheated water from an ordinary hot water system enters the inlet 35 to compartment I I at approximately .140 F. As the water enters the first chamberof thecompartment I I formed by the fins32 and the inner walls of the compartment II, violent circulation takes place onl both sides of the, inclined faces 33 and 34 of the'baile I4.- As the-wateris Withdrawn it aeoasvc moves successively from chamber to chamber between :the ins 32 'and the inner walls ofthe compartment Vil. Similarly the water Yenters compartment i2 throughfthe passage vf'and advancesirom chamberto chamber to the outlet 3l of the compartment l2; The thermostatic switch 3S, which is located near the outlet '31, extends through holes' in the( i'lns 32 in the nnal two chambers of compartment 'I2 to regulate 'the outlet temperature ofthe water at approximately 190 to 195 F.

The heating elements cast within the baffles M and H5,- whi-ch are madefof excellent heat conducting metals, such asrk aluminum or aluminum alleys provide-'uniform heet on three sides of each chamber formedby the baiiie face and 'paralleli-ins. The current to these heating elements is regulated 'to 'give the desired outlet temperature bythe thermostatic switch 538. Y

in the form' 'oi the invention 'shown in Figs. 5 '6, water 'now is 'the same as described in the previous oim, but' a minimum temperature of 165 El. is maintained within the chamber ll. Thiais' accomplished by having two heating elements each` baite,- one controlled by the thermcstatic switch 3,8" and the other controlled by the 'thermostatic switch M. 'When the outlet temperature reaches 190 vto 195 F., the heating element Iit in each bailleis cut out-'and 'the heating-elements 'Mi Aremain on, as' the 'temperature in compartment H 'is not above 165 F. in oom- Dalllellt Il, at which time they are Clit Out. This .maintains an the water 'in compartment Irl at a temperature fof-.165F. for rapid heating to ieoaor .latini when the other elements it' are again 'ener-gize'dL!l While the heater is 'adapted-for use for heating anyliq'uid, itis particularlyadapted for heating water rapidly to -'atemperature suitable for st'e'rilizin'g 'glassesland `sirnilar'vess'els, and the above description ofthe operation thereof particularly refers to such use. When so used the'valve controlling now oi liquid 'through the heater is in vthe .inlet 'connection and 'the outlet connection is open to the atmosphere, and accordingly the liquid iin 'the heater is -at atmospheric'pressure at al1 times.- f

what .i claim is: i y I .1 -Ina 'li'qid heater, a housing, a partition dividing said housing into a pair of compartments, an inlet connection leading into one of lsaid compartments, a discharge connection leading ffrom the'otner of said compartments, said partition having a lpassage therethrough connecting said compartments, a baiile in each compartment interposed between said passage and con- 'baite in each compartmentinterposed between 'said passage` and-connection, Aheating 'elements in said loafes 4'and Vtemperature responsive mea-ns controlling energiz'ation of said heating elements.

'3. In ya liquid heater, a housing, a partition dividing isa-id Ihousing into fa pair of liquid 'compartments, `r anfinlet connection leading into one of .said compartments, ia discharge 'connection leading ffrom. 'thel other' of said compartments,

said partition having a passage therethrough connecting said compartments, 'aninclined baffle in veach compartment-interposed between said passage and connection, said baffle having a pluralit'y of 'parallel 'ns thereon dening liquid passages'between the same, heating elements in said baiiles and temperature responsive means extending across aplurality of said liquid passages controlling energization of said heating elements.

4. In a liquid heater, a housing, a partition dividing said housing intoa pair of compartme'nts, an inlet Vconnection leading-into one of said compartments-a discharge connection leading' from "the other of said compartments, said partition having a passage therethrough diagonally opposite both of said connections connecting said compartments, an oblique bale in each compartment interposed between said passage and connection, heating elements in said baiiiesand temperature responsive means controlling `energ'i'zation of said heating elements.

5. In a liquid heater, a housing, fa partition dividing said housing into a pair of compartments, an inlet 'connectionleading into one of said compartments, a discharge connection leading from the other of said'compartments, said partition having a passage therethrough connecting 'said compartments, a'baie in each compartment' interposed between said passage 'and connection, heating f'elements 'in Said bafiies and temperature responsive means extending into said other compartment in adjacency to'said baiile 'controlling energization of said heating elements. '6. `In a liquid heater, `a housing, a `partition dividing said housing `into a pair of vcompar'tments, an inlet connection leading into oneof said compartments, a discharge connection lead- Ying from the other of said compartments, said partition having a passagetherethro'ugh connecting said compartments, a baite Vinea-ch compartment interposed 'between said passage and Vconnection, a pair of heating .elements in each of said baiiies, temperature responsive means inlone of 'said compartments controlling energiza'tion vof one heating 'element of each pair, and temperature responsive means in 'the other fof `said com'- partments controlling energizat'i'on of the other heatingelementof ea'chp'air. 4'7. In a liquid heater, fa housing, a partition dividing said housing into a pair of compartmentaheatingmeansin each of said compartments, each heating-means having fa pair of heating elements, temperature responsive means in one of said compartments 'controlling energization 'of one :heating element Vof each pair, and 'temperature responsive meansfin theother of said'compartments controlling energization of the other heating element of each'pair, said heater having means for' passing liquid into engagement with 'the heating means in said compartments successively.

8. In a liquid heater, ra housing, ra 'partition dividing isaid housing into a pairof compartments, an inlet connection leading into one of said compartments, a1discharlge 'connection leading from the other of said compartments, said partition .having a passage'therethrough connecting said compartments, a-baflie in each compartment interposed l'between said 'passageand Imen'ts, :an inlet connection kleading into one` of said compartments, a discharge connection leading from the other of said compartments, said partition having a passage therethrough connecting said compartments, a baille in each compartment interposed between said passage and connection, said bailles having marginal edges lying adjacent but spaced from the walls of said compartments and parallel flat faces from which flat faced fins extend perpendicularly, and heating elements in said baffles.

10. In a liquid heater, a housing, a partition dividing said housing into a pair of compartments, an inlet connection leading into one of said compartments, a discharge connection leading from the other of said compartments, said partition having a passage therethrough connecting said compartments, a baille in each compartment interposed between said passage and connection, said baiiles having marginal edges lying adjacent but spaced from the walls of said com- A partments and parallel flat faces from which fiat faced fins extend perpendicularly, said fins extending into adjacency with the walls of said compartments to divide said compartments into a plurality of heating chambers defined by said walls, fiat faces and fins, and heating elements in said baffles.

11. In a liquid heater, a housing, a partition dividing said housing into a pair of compartments, an inlet connection leading into one of said compartments adjacent an upper corner thereof, a discharge connection leading from the other of said compartments adjacent an upper corner thereof, said partition having a passage therethrough connecting said compartments adjacent the lower corners of said compartments diagonally opposite said upper corners, a baille in each compartment inclining upwardly toward the outlet side thereof, heating elements in said baiiles and temperature responsive means controlling energization of said heating elements.

12. In a liquid heater, a housing, a partition dividing said housing into a pair of compartments, an inlet connection leading into one of said compartments adjacent an upperl corner thereof, a discharge connection leading from the other of said compartments adjacent an upper corner thereof, said partition having a passage therethrough connecting said compartments adjacent the lower corners of said compartments diagonally opposite said upper corners, a baffle in each compartment inclining upwardly toward the outlet side thereof and extending to adjacent the opposite walls of said compartments, and having fins thereon extending to adjacent said partition, the vertical wall opposite said partition and the top and bottom walls of said compartments, heating elements in said bales and temperature responsive means controlling energization of said heating elements.

13. In a liquid heater, a housing, a partition dividing said housing into a pair of compartments, an inlet connection leading into one of said compartments, a discharge connection leading from the other of said compartments, said partition having a passage therethrough connecting said compartments, an oblique baille in each compartment interposed between said passage and connection, said baiiies having parallel hat faces from which parallel flat faced ns extend perpendicularly, and heating elements in said baiiies, said baffles and ns being removable from said compartments as a unit.

14. In a liquid heater, a housing, a partition dividing said housing into a pair of compartments, an inlet connection leading into one of said compartments adjacent an upper corner thereof, a discharge connection leading from the other of said compartments adjacent an upper corner thereof, said partition having a passage therethrough connecting said compartments adjacent the lower corners of said compartments diagonally opposite said upper corners, a baille in each compartment inclining upwardly toward the outlet side thereof and extending to adjacent the opposite walls of said compartments, and having parallel fins thereon extending to adjacent said partition, the vertical wall opposite said partition and the top and bottom Walls of said compartments.

15. In a liquid heater, a housing, a partition dividing said housing into a pair of compartments, an inlet connection leading into one of said compartments, a discharge connection leading from the other of said compartments. said partition having a passage therethrough connecting said compartments, a baille in each compartment Yinterposed between said passage and connection, said baffle having a plurality of parallel iins thereon deiining liquid passages between the same, one of said ns having an opening therethrough, heating elements in said baffles, and temperature responsive means controlling energization of said heating elements extending through said opening in adjacency to but spaced from the wall thereof.

LESLIE G. BOWEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,146,431 Homoky Feb. 7, 1939 2,237,808 Berg Apr. 8, 1941 2,421,562 Hynes June 3, 1947 2,511,848 Hill June 20, 1950 

